I'm playing through a couple of games concurrently right now, alternating between them:
- Sonic Rivals
- Super Monkey Ball Deluxe
- Smash Ultimate
I really love Sonic Rivals, it's a lot of fun and the game environments are just beautiful. I love the variety and uniqueness of the game's environments as well -- there's all kinds of cool scenes and gimmicks that just aren't that common among many Sonic games.
I've also played a bit of Sonic Adventure DX and Sonic Advance 3 recently. I already played through the games in full again a few months ago, but always love going back and just playing a few levels here and there, or playing with the precious Chao or walking around the awesome hub worlds and experimenting with mods.
Super Monkey Ball Deluxe is one of my favorite non-Sonic games of all time. I love Super Monkey Ball 1 and 2, and just recently had the opportunity to pick up a copy of Deluxe as thankfully the Xbox 360 supports backward compatibility for it. Just an extremely fun and extremely challenging game, love playing it alone and with friends/family. All kinds of beautiful environments too and the characters are fun. I'm not a fan of the newer monkey ball games, and am especially no fan of the character redesign... the old designs were great, there was no need for Sega to change them.
Lastly, Smash Ultimate is a great game and super fun to play with family. We unlocked every fighter in a couple of days but are still working through World of Light. Loving how beefy that mode is, and challenging -- has proven to be the kind of thing you can't get through in one sitting unless you're way better at this game than I am lol.