If the name doesn’t ring any bells, then you probably need to read more comics. Pietro and Wanda Maximoff are siblings, sometimes known as the superpowered mutants Quicksilver and Scarlet Witch respectively. In comic book history, they are also the children of Magneto.
In a quirk of licensing, both Fox and Marvel/Disney have the rights to the characters of Quicksilver and Scarlet Witch, and are both choosing to exercise them for X-Men: Days of Future Past and the Avengers sequel respectively. Fox beat Disney to the punch recently by casting Evan Peters as Quicksilver. Could the casting of Wanda Maximoff be too far behind now?
X-Men: Days of Future Past is set for released on 23 May 2014 from Fox. The Avengers sequel will be out on 1 May 2015 from Disney.