Found this on YouTube not really a exploit but..
Note: None of these are mine
Done in 3.0.2
Video 1: [ame="http://www.youtube.com/watch?v=5u07qEk10Rc"]http://www.youtube.com/watch?v=5u07qEk10Rc[/ame]
Not sure if this still works since Wall jumping got nerfed...
Video 2: [ame="http://www.youtube.com/watch?v=G7Z9NyAgxCs"]http://www.youtube.com/watch?v=G7Z9NyAgxCs[/ame]