Well considering that knowledge of the production team's past and current projects is also a requisite to understand some of the jokes, (which seems to appear every other minute or so) I'm listing Negima!? as one of the "deep" shows for this season
The best part with this type of direction (referencing other works) is that you always find something new to appreciate when watching the episode again.
And um just so my post has something episode 5 specific...
some observations:
Ayaka is now girl 13. (in OP)
someone in the staff likes sculptures...
nodoka gets entangled in vines, konoka gets entangled in tree branches, the next girl is entangled in...?