100 BC, by Jacqueline Rayner. kind of a crazy premise, really—the 6th Doctor and Evelyn travel back to 100 BC to try to ensure that Mr. and Mrs. Caesar "do the deed", guaranteeing the existence of Julius Caesar. well, the Doctor does; Evelyn believes that the world would be better off with a Julia Caesar, and tries her best to ruin the mood. everything turns out right in the end, though.
My own private Wolfgang, by Robert Shearman. have you ever wondered what would have happened if Mozart hadn't died quite so young? or perhaps had lived to, say, 100 years old? now you don't have to. got a bit confusing with all the different Mozarts (clones, Mozarts from the future, the original Mozart himself), but funny.
Bedtime story, by Joseph Lidster. pretty eerie. a family is plagued by a strange curse: whenever a son is born, the boy's grandparents are sure to die soon after. the Doctor quickly works out that a bitter entity is the cause. spurned lovers, death-like sleeps, and a monster set on revenge. cool.
100 days of the Doctor, by Paul Cornell. the Doctor is infected with a virus that will take over his body in a mere 100 days. along with Evelyn, he travels backwards and forwards (and sideways) in time, trying to find out when he was assassinated and stop his death before it occurs.