Erin Jessica Cahill (born January 4, 1980) is an American actress. She is best known for her roles as Jen Scotts in Power Rangers Time Force (2001), as Ted Mosby's sister, Heather, in How I Met Your Mother (2005), and as Kendra Burke in Saving Grace (2007). She had a recurring role as Felicity in the ABC series Red Widow (2013). She is also noted ...