The combination of bone translation and scale bone tools are the best way of getting those funny "Slapstick effect". Dragging scale bone tool on a bone causes the length of the bone to increase. It, combined with bone translation tool get dynamic movements.
http://www.youtube.com/watch?v=IsjeEgzDD5E
http://www.youtube.com/watch?v=80R2Hgv6010
"Slapstick tools"
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