It'd be pretty cool to have a TI-99/4A emulator. I'd love to be able to play Parsec on my Wii!
I had a TI-99 until it broke and no longer works... I didn't have many games for it, just Parsec and a few others that were not that interesting.. When I was younger, TI-Basic was my first experience with any sort of programming.
There are a number of emulators out there for Windows and Linux:
http://www.99er.net/emul.html