The fact that Comedy Central is your first example of an ideal advertiser means that you're probably not in a high-CPM niche. That's okay, but it means you probably ought to be running a couple million impressions each month to make direct sales realistic.

At lower volume (say, a 500k/mo+ impressions) you can investigate banner networks like Valueclick, Casale, etc. If you go this route, hopefully you're not turned off by flashing punch-the-monkey ads. It's not high-brow advertising.

Also look into augmenting your income with the contextual link networks -- Infolinks, Kontera. It's decent supplemental income.

For a general-interest entertainment-type site without a high page churn (that is, not a forum or social network), I'd aim for $2.50 overall page CPM. This might require lots of ad units and creativity, but you can make that happen without direct sales.

(Apologies if I've totally misread your niche -- in that case, hopefully all this is useful to someone else.)