Everyone's had it... Buy some Wifi Card and find out there's no Linux drivers that work with your favorite flavour... I just had a similar experience yesterday; I lost my X-Micro card (Atheros chipset), and all I had left was my Speedtough 110 (no typo). It just won't work.
So I spent the rest of the day looking for the X-Micro card, and I ended up tidying half my house then finally finding the card I was looking for, only to find out that when I inserted the card and went to install the drivers, my rawhide machine (or actually the F7 kernel), could not install madwifi because if wasn't build against rawhide yet, no surprise there. A previous version of madwifi however, build against an older kernel, would not load because of something with 'hal' -don't ask me. Again, no real surprise here either.
So I installed the latest fc6 kernel, which I know madwifi has been built against. While expecting major problems due to some package in fc6 vs. f7 requiring a f7 kernel, I was surprised to see it work.
It just works! I'm glad to know that I'll be able to do some Revisor tricks at LinuxTag, and still have networking ;-)