Most nearby stars are unlike our Sun: Three-quarters of the stars in our galaxy are M dwarfs, with masses from a half to a tenth that of the Sun. However, there are outstanding challenges to understanding these common stars, from the origin of their magnetic dynamo to how they spin down. Understanding stellar physics is important in its own right, and because of the impact stellar phenomena have on orbiting planets. I will discuss new observations of spin and magnetism in M dwarfs, and how we tie these measurements together to investigate stellar evolution. I'll then turn to efforts to discover and characterize exoplanets that can inform studies of planetary evolution.