Here are three medium difficulty, rebus puzzles,
A work in progress:
(With help from ffao!) Python = (pai + marathon - mara)
(Per Aiden F. Pierce, who beat me to it!) Rattlesnake = (rat + less + N + ache).
Hypertext mark-up language = (Hyperbeam - beam + text) + (mark + up) + language
Python? (pai + marathon - mara)
Rattlesnake (rat + less + N + ache).
Others have already covered the other two.