Repurpose an Old Wifi Router for the Internet-of-things : 5 Steps (with Pictures) - Instructables
Old Dog, New Tricks: Mod a Linksys WRT54G-series Router : 13 Steps (with Pictures) - Instructables
Linksys Router Repair - iFixit
Amazon.com: Linksys WRT1900AC Dual-Band+ Wi-Fi Wireless Router with Gigabit & USB 3.0 Ports and eSATA, Smart Wi-Fi Enabled to Control Your Network from Anywhere : Electronics
High Performance Linksys WRT54GL Wi-Fi Wireless-G Broadband Router with built-in 4-port Switch and Wireless-G Access Point,Internet-sharing Router with 2 External Antennas up to 54 Mbps - Newegg.com
The WRT54GL: A 54Mbps router from 2005 still makes millions for Linksys | Ars Technica