Some users have recently had their accounts hijacked. It seems that the now defunct EVGA forums might have compromised your password there and seems many are using the same PW here. We would suggest you UPDATE YOUR PASSWORD and TURN ON 2FA for your account here to further secure it. None of the compromised accounts had 2FA turned on.
Once you have enabled 2FA, your account will be updated soon to show a badge, letting other members know that you use 2FA to protect your account. This should be beneficial for everyone that uses FSFT.
Learn Linux by throwing a copy of Ubuntu or Mint on there?
Add a large HDD and install FreeNAS, and you've got yourself some network storage (if you're ok with the power usage)!
Make a MAME-powered arcade cabinet?
Make a retro gaming box (maybe a little too fast for a lot of DOS games)?
Donate it to a person or an organization in need?
Thanks for the suggestions. I wrote them down. I think setting up a web server is pretty neat idea. It will be a useful experience. I'll look into it when I finish up my current project.
Donate them, or I use them for file backup servers. Instant, hassle-free backups, really gives you no excuse not to have them. FTP is easiest, otherwise if you can't open ports on your router or don't have a static IP, use something like Bittorrent Sync or GoodSync.
A webserver is a good idea too. Keep in mind that for both of these ideas, it might be more efficient to get a low power solution like an Intel NUC or Raspberry Pi (what I recently started using).