StarDestroyer.Net BBS

In light of my family's inability to understand a bandwidth cap, I've decided that I need a monitor for every computer in the house.

While this has been done for the Windows ones, I need one for this Ubuntu computer.

Does anyone know any that will allow me to see how much has been up/downloaded over the month?

Try VNStat http://www.linux.com/feature/61201

It would actually make more sense, in my mind, to monitor this on your router. Is your bandwidth cap a limit in total data transfer, or is it like 95th percentile?

If you have a Linux router, an OpenBSD router, or a Cisco router (or something else that's really awesome, i.e. in the extremely unlikely event you have a Juniper in your house), or certain models of Cisco switches, you can set rate limits, that would ensure you stayed under your limit, albeit at the expense of speed.