If you are trying to limit the speed of torrents, most of the client software out there will allow you to do this.
Otherwise, many routers will allow you to limit\disable internet access, the BT HH2 has a simple on\off for time of day for each device connected. (I've just checked mine)
And don't forget, if you want a simple on\off for internet access across the board, a plug-in timeswitch can be had for £2...
Edit, I've had a flick through the DSL version's manual, and I can't see anything for time-based limiting on that router.
Edited by deleted (Fri 23-Jul-10 19:53:43)