I'm torn between going for LD 40 or playing in my once a month netrunner tournament. We shall see.. But I will suggest some themes. My three themes are:

Awkward Pauses

Pausing a game isn't often used as a useful mechanic so it would be interesting to see what people come up with. Also it could be used as a story theme instead of a mechanics theme.

Equivocation

Has a couple of different meanings which tends to lead to a bit more variety in the output of the jam but not too open ended as to be paralyzing (such as one of the theme choices from the last LD: protect it). In particular is used as a term in magic when you are forced into a choice but it seems like random chance or a free choice.

Blessed with Suck

This is the silly one. Essentially the gist is that you have a super power that is very inconvenient or completely useless and you must find a way to make it useful. I'm sure there are also story themes you could use with it as well.
http://tvtropes.org/pmwiki/pmwiki.php/Main/BlessedWithSuck