I'm recommending Martha Jones-centric fics all this week but they're not all Martha/Ten.
Story A Little Shelter
Rating: All ages
Author Summary: There's a house on Bannerman Road.
Characters: Martha Jones, Sarah Jane Smith, Luke Smith, Clyde Langer
Word Count: 2233
Recced because: I am a complete sucker for Year That Never Was stories, especially those in which Martha meets up with and is helped by former Companions of the Doctor. In this one Sarah Jane helps Martha with the Doctor's plan; there's also a brief cameo by Ace, which is spot-on, and the whole story is marvellously well-written.
"Where'd you get these?" Ace asked, marvelling at the quality of the forgeries on her return from Wales.
"I met a woman with an alien super computer living in her attic."
"Oh, the usual then."