Glow bracelets tucked into printable cards (doc available at link) makes a trio of fantastic Star Wars Valentines for kids, nerds and nerdy kids alike. I love them so much, I won't gripe about light saber color accuracy.
Glow in dark cups! Activate (snap) then put glow stick bracelet in base of a solid-colour plastic cup, The put clear plastic cup on top pushing bracelet down. Fill with drink - once dark the cup will glow. nice for bonfire night.