OpenWrt
From charlesreid1
OpenWrt is a lightweight operating system that runs on routers.
Dropbear - this is a classic Linksys WRT54GL router running OpenWrt.
Widy - this is a TP-Link 3040 battery-powered pocket router running OpenWrt.
Also see OpenWrt/Opkg for creating opkg packages (ipk files) to automate/ease installations on OpenWrt systems.