LifeHacker has a great article on how to hack your Linksys wireless router WRT54GL.  The list includes things such as a signal booster and throttling bandwidth (QoS).

Of all the great DIY projects at this year’s Maker Faire, the one project that really caught my eye involved converting a regular old $60 router into a powerful, highly configurable $600 router. The router has an interesting history, but all you really need to know is that the special sauce lies in embedding Linux in your router. I found this project especially attractive because: 1) It’s easy, and 2) it’s totally free.