There was a Windows 2000 bug that would allow the computer to be crashed via a malformed IrDA packet. Of course someone crafted a Palm Pilot app to zonk all the vulnerable PCs in the vicinity. It worked on servers as well. Endless fun for a little while.
Some laptops had them, and came with IR remotes. Some of the marketing was around using those laptops as "media centres", and you could control them from the sofa while it was plugged into a TV.
