For the past few weeks I've just been hella addicted to L4D so that dominates the ol free time. Sometimes on Team Fortress 2.
Trying to get back into Pokemon Pearl to get at least the first 100 Pokemon, and Yoshi's Island.
Super Mario Bros. 3! It's so well designed... I recommend anyone making a platform game to play it. If you've already played it, play it again. And don't get an emulator and use the ever-tempting quick-save, it ruins everything!
Not playing much else, apart from the occasional Mirror's Edge and Cortex Command
Yes, it's not official, but some of it is pretty good. You can get things like proper supports, which make the coasters seem a bit more realistic rather than the built-in supports. You can also get particle effects and things.
Granted, the lighting isn't perfect by far, but if the ride and theming are nice enough I don't think that matters. Several mods have been made by users to allow for dark rides, I believe. Space-type rides can also be made using the mods:
I currently try to beat Hagane for the snes.
For thoses who don't know that game, it's a japan-exclusive, in wich you play a samurai robot.
If that isn't enough to make you run to get it, then maybe the fact that the combat engine is the best and the most complex I've seen on the console could make you get it, maybe just to get inspired for your own games. But really... Robot ninjas are the coolest thing ever! So it should be enough of a reason to get that gem wich we couldn't get our hands on before.