As of versions 0.76 and greater, there is a schedule in BitComet under "preferences". This enables you to run tasks to run only at a certain time. To use it, just configure the scheduler and download a torrent. Leave BitComet running for the night, and it will download in the interval that you specify. (It is suggested that you use the most recent version of BitComet, the link for which is in my signature.)
BitComet version 0.71 and all subsequent clients are a complete rewrite of the client, so there are bugs. It is advisbale to people having trouble with the newer client to download version 0.70.
I think the "add" Dr. WTF was refering to was the one only in version .70. There is a picture of this "add" on the wikipedia BitComet article. The "add" that is referred to is only in version .70, and is absent from all other clients. Just trying to figure this whole adware thing out.