I wrote a really obscure DW Crossover story here:
Spanner in the Works(Doctor Who / On the Up Crossover)
(Tenth Doctor, Martha; All Ages)
http://www.whofic.com/viewstory.php?sid=27689The Doctor and Martha are on a quest to locate an alien signal and borrow a spanner. Sam has got a spanner and is willing to lend. Should be simple, right? Of course not: there's family rows, aliens, saucepans, unrequited love and lots of cups of tea.
It was for my sister's birthday (I tweaked it a bit from her special, illustrated version...). It's mad, but hopefully makes sense, as I realised very few people are likely to remember the show I'm crossing with. But it's a sitcom, there's Joan Sims, Sam Kelly and Dennis Waterman & it's all a bit of fun.
( Explanation for those who want it )