Do what I did, find the busiest hall of your school, during the busiest passing time see her passing, so everyone's around spot her coming and just yell out the question... "HEY (your girl's name), I LOVE YOU, LET'S GO TO HOMECOMING OKAY?!" She thought it was really cute and everyone laughed, so I think it was a good one. Bonus points if she's by all her freinds, so she can brag about how sweet yet goofy you are