#BOFH excuse #264:

Your modem doesn't speak English.
#BOFH excuse #3:

electromagnetic radiation from satellite debris
#BOFH excuse #298:

Not enough interrupts
#BOFH excuse #363:

Out of cards on drive D:
#BOFH excuse #24:

network packets travelling uphill (use a carrier pigeon)
#BOFH excuse #228:

That function is not currently supported, but Bill Gates assures us it will be featured in the next upgrade.
#BOFH excuse #263:

It's stuck in the Web.
#BOFH excuse #422:

Someone else stole your IP address, call the Internet detectives!
#BOFH excuse #84:

Someone is standing on the ethernet cable, causing a kink in the cable
#BOFH excuse #435:

Internet shut down due to maintenance