Play a different game. That's what I did.

Spiral Knights has extremely slow updates, moreso than any other MMO I've ever played.

Naysayers will be quick to point out that thread that highlights all the updates SK has undergone since its launch last year, but, how many of those updates really pertain to entertaining endgame content with longevity?

As it stands now, the endgame of SK is as follows:

1.) Run FSC for cash.
2.) Merchant in the AH for cash.
3.) Try to fill your arsenal or get good UVs for your arsenal using said cash.
4.) Lockdown
5.) Shadow Lairs? (I barely count these, since there is very very little reason to run them more than once, ever.)

is gather costumes, crowns/ce, collect UVs, and maybe doing challenge runs (like the example you gave)--all things you just said you didn't want to do.

Aside from that, chat a bit with friends, and wait for new content. But even thats unrewarding, since they are doing 1 new content per 8 months period, in which case, they put out new content and you get bored within 3 days. Really, its the sad reality of this game. There is nothing to do once you reach the endgame. And they can't (i don't mean this cynically, maliciously, or mockingly) produce new content quick enough to keep its player base's interest.

It is 99% up to the player keep his own interest, and 1% up to the game. a few random ideas tho:
Make an all bomber outfit, and play through the same boring places a couple more times.
Make an all gunner outfit, do the same.
Try and do a few of the dungeons solo. FSC, Jelly, Gauntlet mission. (only viable if u have a decent comp and connection)
Try to get into Lockdown (but i don't really find lockdown to be that much fun).

So given that you don't want to do any of those things (and i don't blame you 1 bit) there really isn't much to do.

Again, no one take this out of context. Not saying OOO is lazy, or greedy, or evil. Just saying that this game has very little depth to it. That if you play obsessively, you'll accomplish everything (content-wise) in short order, and then they have not yet (and likely never will) be able to add enough content to stay ahead of any sort of interest curve.

All that being said, i have put an AMAZING amount of time into the game. Altho over half of that is using it as a chat service with my brother before he moved to the same city i live in. The rest of my time has been gathering costumes--which doesn't really involve actively PLAYING the game, but rather playing economy and buying stuff.

Until (and i don't know if they ever could. maybe the programming code is so muddled that it takes 8 months to program one new dungeon, and then trouble shoot everything that got jacked-up. or maybe the profit margin is such that one more paid employee would consume the remaining profits they make) but until they can find a rhythm that see's new content added in regular and frequent installments, this game is going to be very newb friendly and a lacking experience for veteran players.

Even for those of us who love grinding, and don't mind repetition, there is a limit. And every hour you play after beating FSC for the first time, is going to be winding down that limited amount of time left in the game.

tl;dr
it gets boring quick. and it appears that OOO will never be able to add content frequently enough to stay ahead of the boredom curve.

not much... unless your a collector the only thing you can do is hang about for updates and events.
The only reason I still play is to troll, play with friends and to chat with the bouses and bousettes that I have met. And above all that I feel bad if i just leave as all that play time seems like it is then wasted.

really what the game needs is some bigger (the ones atm really only exist for those who read or who have friends that read the forums ) community events otherwise there is always staring blankly at the screen while your avatar is chillin in front of the AH.

What it needs is frequent and consistent updates. If we could expect a new dungeon at the first of every month. But who knows. For whatever reason i am assuming this is impossible, or they would have done it already.

Honestly, at this point, even if they just made it tweaks to what we already have.

This Month: OH NO.
1. Charged Quicksilver jelly palace and the Quicksilver Jelly Queen King....OH MY.
2. Hell Hath Frozen OVER!!!!! Ice storm Citadel and the Abominable Duke!!! if you dare.

Stuff like this would be fun. And would be worth a handful of runs. It'd also be neat b/c all of a sudden everyone's fire max gear for vana wouldn't quite cut it. and maybe some shock max gear for jelly palace would be in order.

Next Month:
1. Vana has been demoted to Tier 2! And the Jelly king has been promoted to T3!!!!!

Vana Palace: Vana now lives in jelly palace.
replace all slimes with skeletons. mini slimes with skulls that skittle across the ground. Lumbers with trojans. Jelly King with a small vana that only has 3 phases.

Jelly Storm Citadel!!!
Replace all firespots with goo that slows you down to run thru. Skeletons with T3 jellies. Trojans with lichen colonies. Slags with...idk, more lichen colonies i guess, lol. Vana is replaced with a giant Jelly-Duke.

Jelly-Duke. He is giant. 5 phases. Everytime you destroy a phase, he explodes glooping a ring of jelly (that doesn't disappear on the floor--so the strategy would be to kill each phase in the same corner of the room, so as to not let him goop up the entire place). Every time you destroy a phase, he shrinks some. In the final Phase, he calls forth more lichen colonies instead of slags.

Tell me that wouldn't make May and June more interesting vs nothing new happening?

I left SK & came back with a new account bc honestly now, why would i want to come back to end-game content? Starting new & fresh is great. I play for the lore & looking SK-ishly awesome! Those people who didn't understand why I came back on a new account are now long gone from this game & here I am having a blast. They're bored & burnt, I'm refreshed & having fun. You fail to see my game style then you won't last long in my type of games.

@ Rommil
Changing the normal RJP and FSC stratums sounds great. =) I wonder if Thunderstorm Citadel would be harder or easier...

Get the prestige I'd say. I'm about 75% confident that they will give something more for high prestige (I'm betting cool crests).

If they had monthly content update:

New monthly content is only available to Pay to Play players (for that month. after that month it becomes free to play content).
During that month shadow keys can give f2p players access to the P2P content.

So its the best of all worlds. Incentive to pay to play. Access (at a cost) for free to play players. Shadow lairs (now free content) gives us more new content (4 new dungeons for all!!!) while still keeping a purpose for shadow keys (access to pay to play content).

This should win for all. I think.

you could give out crs and ce to new players. =D

Now you're a hero...

Hoard materials. Try to reach 30k of something.

Get rich, spend the money on better gear. If you have all the gear you want, use the money to buy Steam games.

Play Lockdown and/or Blast Network.

Be social, chat with friends/guildmates/interesting individuals.

Develop new and peculiar methods of completing various levels.

To answer the OP.

You now wait in haven one last time with the most closest friends in the game you have and look back on what you've "accomplished" in the game. You think on whether each thing you did was worthwhile, meaningful, and overall enjoyable to your gaming experience, and to those around you. As you ponder on these thing, you bid your friends and enemies farewell as you slowly press the sequence of the ESC key and LeftClick the Quit button.

As you look at your computer's customized desktop background, you think over all the great times you've had in the game.

You shut down your computer.

You head off for bed.

You awaken in a new day, and Spiral Knights is now nothing but a nostalgic reminisence of the past as you get out of bed and continue with life, still with the hanging feeling of whether you really ended on a good note or not, and whether the game really "ended".

...

Sorry, just saw the ending of Mother 3 for the first time and uhh... yeaaaah....

the fault really isn't in terseakaff, its in the lack of new content. (accepting that he's not a fan of lockdown, that is).
I mean, there is a reason no one is still playing mario to the NES. (i know someone who thinks themselves a contrarian will come in and say "oh but i still am")

Try and complete 100% of the achievments.