I don't climb, so I can't give any specifics. The Bucks County Covered Bridges ride was hilly according to some people... I took the flat course...
I have heard reports of good climbs around Jim Thorpe. I don't know the details. My favorite ride near Jim Thorpe is the Rail Trail through the Lehigh Gorge, and it is very flat... But beautiful! There are some wicked looking hills in the area that I haven't ridden.
If you wander further north into the Endless Mountains, there is a climb up near Ricketts (sp) Glen that would be a killer... it is hard to drive up.
I have also heard of another hilly organized ride near the NJ PA border, I think it was called "Gap to Gap"
If you are interested in a short steep climb, one hill local to me might be nice. Once a year they have a car hill climb event called Giant's Despair
I am actually going MTBing this weekend at Jim Thorpe. I can check out the local roads to see if it looks like a good road climb. I imagine Bucks county is very hilly, but was looking more for a true mountain climb(at least by PA standards), where I can soak in the view at the top and feel some accomplishment. Giant's despair looks wicked! Maybe I can do that after a lose a few more pounds! Thanks!