I've found that speeding up lectures can make them more
interesting and exciting.

I hypothesize that we humans have a faster
download rate than our teacher's upload rates.

A great example is
Prof. Gilbert Strang who has a great course on Linear Algebra on MIT's OCW site. Prof. Strang's teaching style is thoughtful and meticulous which I really appreciate. However, if I were in his class I would get frustrated because I like to listen to the material faster than he presents it. I find that I enjoy Prof. Strang's lectures the most at about 2x the normal speed, and I've found that most lectures are much better at least 1.5x faster than their normal speed. Try it out, you might discover a great new way to learn.

VLC Media Player - 3 Ways of Changing The Playback Rate:

Best way: Use the keyboard shortcuts "[" and "]" to change the rate by +-10%.