UnusAirPort Extreme

Donate them to a church or other organization

Use them to "extend" your current network if you need more wireless coverage in remote areas

Use them to set up a network for "guests" or the kids......so you don't have to give them the password to your private network

Sell them on eBay and make a little money

Take them to a recycling center if you do not need them for any other purpose

Some models with a USB port can be used to make a USB printer, into an AirPrint printer, and some models with a 3.5mm aux jack, can be used to make any wired speakers, into AirPlay compatible speakers.