It was about two kids, probably brother and sister, whose uncle (I think) sent them on missions back in time to capture little monsters that were causing trouble, and then relocating them to a different period where they could be useful.
I think that the time travel sequences started on small ship that was in a cannal on the floor.
I think it was on air around 2009, but its probably older since shows take a while to come air where I live. I used to watch it on tv, probably Fox Kids or Jetix.
Also, there may have been an episode with a tiny ice elephant, that ended up making ice cream, and somehow Napoleon was involved, but im really not sure about it :/