OK. I think the TV show is kind of cute and it always has some kind of lesson involved. So, when my kids decided they wanted to see this movie, I decided to tag along. I wish I'd stayed home and watched the TV show instead.
The fact that the humor is silly and unoriginal is the least of the problems with this movie. The plot is next to non-existant, the characters seem to exist in a vacuum, and, worst of all, Gadget does not carry any lesson whatsoever. It appears that Disney took all of the things that make Inspector Gadget work on TV and tossed them all. To be fair, my younger child (8 years old) liked the movie but the older one (10 years old) came away thinking it silly (he was too old for the youth humor but too young for any of the adult humor).
Generally, I like Disney films but this one misses by a mile. It is OK for a very narrow age band (say 7 to 9) but a must miss for everybody else.