Kay, um...
Super Mario Galaxy - I beat the main story a LONG time ago, but... I have like 7 or 8 more stars to go, and I just can't seem to muster up the attention to get them all. It was a fun game though, even if I spent far too long trying to 1cc the Trial Stages before giving up on that goal (I DID 1cc the ball-rolling stage, though). I occasionally pop it in and try to force myself to finish it, though... Success is at ~5% to this mission.
Perfect Cherry Blossom - Good god even on easy I have trouble. I just assume I need more practice or something - my best characters are ReimuA and SakB for some reason, though.
Pop'n Music - I have 9 and 10, but I find myself playing 13 almost exclusively. I'm working on improving my skill, but Hyper stages still manage to absolutely obliterate me. It is fun though, especially with more than one person trying a run. Home version means unlimited tries! Yay! It's a shame that it never got released in the states, though.
Shining Force - I find this fun DON'TKILLME. I got as far as the first Pao village (I powerlevel characters, and my friend advances the plot, so right now, I have two Vicars - Khris and Lowe), but I refuse to go any further until I recruit Jogurt. I saw him once, saved... And now, I can't seem to find him again. If I missed him, I'm gonna start a new game...
Also, if this game has an actual plot other than "there's the big bad, go kill it," please tell me.
Billy vs. SNAKEMAN - This... Is a wierd game. Since you're actually limited to what you can do in a single day, this is enough to keep me playing... And playing... And playing... With even three characters. They're named for video game references of course... But yeah. WilKnights, Van Burace, and DemonIrwin. No downloads or anything, and getting stuff is pretty easy... Though the action limits can be frustrating. It's actually a simple system that relies on a RNG for about 90% of the things that go on in there (Hatbot's younger sibling or something?). You have levels, which determine how many dice are rolled for when something requires that stat, strength (which for each +1 strength, that value is added to the roll), and range (normally, you can only get 1-10, no matter what your STR bonus is, but if you have a range bonus, like a +1 for example, your highest roll would be a 11 instead). Doing regular missions takes 10 stamina, special missions take 30, and there's other actions that take different amounts otherwise. Missions are given to you fairly randomly, sometimes requiring, say, two dice that have a value of 7 or more, or one die that requires a roll of 10, or even four dice that require a value of 3 or more. Your stamina refill rate and max chakra values go up as you gain higher ranks. Stamina refills to your max value at rollover each night (which is about... 1 - 2 AM central time), and chakra is adjusted to half its maximum value.
If you want to try it yourself, here's the link (along with the character name of my main):
Be the Ultimate Ninja! Play
Billy Vs. SNAKEMAN today!