I use mine the most for playing sound roms.
Chris Covell's tech demos are cool to see running on real hardware.
There are lots of translated HuCard games. Even if many could be completed without knowing what is being said, it's motivation enough to give some games another playthrough. Some that I know of are Son Son II, Bikurriman World, City Hunter, Lady Sword, Gekisha Boy, Aoi Blink, Die Hard, Gaia no Monshou ("Langrisser Zero") and Maison Ikkoku. Tom was working with someone on a translation of Makai Hakkenden Shada (Ys style game), but I don't know if anything was ever released.
Aetherbyte recently released a Protocade rom.
There is a voice sample demo floating around with crystal clear (for 16-bit) Lunar SSS singing.
The COURAGE diskmag.
Tom's Famicom/NES game conversions.