New Apps come from people who have the time to write them. Donations help write more applications faster. Also, its up to the person to decide when to release new Apps. Try installing iApp-a-Day. Those were 30 new Apps developed by Sean Herber during the month of November.
Many usefull ones like Pumped and Piano. Other plain fun!
"Pumped" was AWESOME and inspired. Man, I'm sad I didn't get a chance to see "piano" (if its what I think it is, its just the tip of the ice berg for what people can be writing in terms of mobile touchscreen music support). I think like many customers, many developers are likely going to focus on February. What's the use is farting around with releases if the major push is going to be somewhat different than what you've been pouring spare time into?
My favorite one had to be the drum one at the end, or maybe the Air Hockey. I can't wait to try out the SDK and create my own Apps for the iPod touch + iPhone