Every time I copy data between my desktop and laptop, I think about how it would be faster if my laptop had gigabit ethernet. I have a gigabit switch and an onboard gigabit NIC on my desktop, but the laptop is slow old 100BaseT. However I do this rarely enough that shelling out 30 bucks for a gigabit PC card would be a waste of money (I could buy a NDS game for $30!).
Then it occurs to me that both computers have firewire, and I have a firewire cable. I know you can do networking over firewire, but does it require a special cable? Out of mainline kernel drivers? Nope and nope. It’s this easy: