Question of the week: what two shows would you cross over?

After a few relatively earnest questions of the week of late, let’s go fun. A crossover, as I’m sure Toby will elucidate on if you ask him nicely, is when characters from one TV show appear on another TV show. The simplest crossovers usually occur in spin-offs (eg CSI and CSI:Miami, Doctor Who and Torchwood), or between shows from the same producers or on the same networks (eg The X-Files and Millennium, CSI and Without A Trace, Scrubs and Cougar Town) but other crossovers do take place (eg Homicide and Law & Order: SVU). 

We don’t have to be so limited though. This week’s simple question is

Which two TV shows would you cross over and why?

And if that’s too hard, just tell us what your favourite TV crossover is?

As always, leave a comment with your answer or a link to your answer on your own blog