Zero No Tsukaima

Louise is a noble girl who is terrible at magic, as her attempts usually result in an explosion. She is nicknamed "Louise the Zero" by her classmates, due to the inability to use any of the four magic elements. Early in the school year at the Tristain Academy of Magic, the second year students perform a special ritual where they summon their familiar, which serves as their eternal protector and partner, and is usually some sort of magical creature. But Louise summons Saito Hiraga, an ordinary teenage boy from Japan, leaving her totally humiliated.

Spoiler: