|1. After the Big Bang Two, Donna was fixed and is slowly getting back to the Doctor.|
2. Ten's clone (TenToo, TenTwo, Ten II, 10.5, Handy, whatever floats your boat) ended up gay, and Rose is slowly digging a hole with a shovel back to this Universe.
3. (Crosses with NCIS) Tony DiNozzo is actually THAT Tony (Tony Tyler, Pete's World) and Jenny Sheppard is actually THAT Jenny. (The Doctor's Daughter, from Messaline.)
4. After the Doctor regenerates, that past incarnation sits at home and watches the current incarnation on TV.
5. Jack turned into the Face of Boe because he has Space AIDs.
This will make all you Moffat-haters at least smile. Elisabeth Sladen's full name is Elisabeth Clara Heath-Sladen. Coincidence or Moffat being a good person for once that he named the next companion after Elisabeth? I'm gonig to go with Moffat being a good person for once.