I don't do stupid shit, so the only time I've gotten a virus was when I was a kid.
I had a game on a CD that I knew was infected with viruses, but I had played that game many times before I got an antivirus and nothing bad happened, so I thought maybe that specific game didn't have a virus (there were multiple games on the CD)
When I tried to copy it to the HDD to avoid using the CD anymore however, my AV (mcafee at the time) gave me a warning, which I ignored thinking that I could just clean the file of viruses after I'd copied it.
Well, that didn't work, the virus spread itself to the entire HDD, the PC got slow and errors popped up constantly, eventually I got my uncle to format and reinstall windows.
It was still pretty nasty though as there was nothing I could do to remove it short of formatting, and at that time I wasn't that good with PCs, all I used them for was browsing forums, downloading stuff over shitty 56k dialup, and playing game demos and GBC roms I had downloaded, and I didn't have a windows CD so I couldn't reinstall it myself.
With all that said, I think that was the only time I actually did something stupid on a PC (disregarding things I've said in chats and such)
On one of my old computers I remember getting a virus that just kept opening different porn sites on Firefox.
Like I don't know how I got it, I didn't download anything suspicious or go anywhere suspicious (certainly not any porn sites), it just happened.
Worst thing was that it was on the family computer and my whole family was home. So basically I had to go between working on getting rid of if and shutting off my monitor so they wouldn't think I was browsing porn.
Fun times, fun times... although I haven't really gotten a virus since then and that was years ago.
Best virus EVAR.
It was probably your family that downloaded the virus.