Anyway, the entire purpose of this post is to declare the following statement:
It is now my personal crack!fanon that Indiana Jones is, in fact, Martha Jones's great grandfather.
I have even worked out the respective timelines.
To start with, I'll work out what we know from respective canons.
The obvious SPOILER for Indiana Jones 4: at the most recent point in the time line, as of 1957 Indiana Jones has a 19 year old son, aka Mutt (age courtesy of the Indy Wiki)
Now, as for Doctor Who canon, as of the start of Series 3 (before all Year That Never Was shenanigans, not to mention time spent in other periods), Martha Jones is 23 years old. Her father, Clive - whom she gets the Jones name from - is intended to be 49 as of Smith and Jones according to RTDs script for the episode.
Now dating in New Doctor Who is somewhat of a problem, what with the year time-skip during S1 which the writers sometimes forget about. But if you remember it, Doctor Who is basically set one year ahead of when it airs. Which for S3 in 2007 would be set in 2008.
Working backwards from that, Martha would be born in about 1985, and Clive would be born in 1959.
And combining the two - well, it's not that hard. As of 1957 Indy has an adult son. It's not much of a stretch to theorise that, perhaps, two years later Mutt goes and meets up with some attractive black British girl, and has a kid with her. A kid which he names Clive (obviously, trying to get away from the "calling all boys Henry" habit)
And if young Clive Jones, grandson on Indiana were to grow up, marry a woman named Francine and have three children - the middle of whom is one Martha Jones - why, that'd make them the great grandchildren of Indiana Jones. And thus proving that Awesome is, indeed, genetic.
(I was considering making a little family tree here, with names and dates and everything, but I decided the HTML was too much effort)
In conclusion, SOMEONE PLZ WRITE ME FIC OF THIS!