Send An "Accidental" Text Message
Pick a 'needs to know it all' friend from your group, and send a text about a juicy secret.
Oops! Wrong person...
Something like "OMG I'm really not supposed to tell you this, but I just found out something MAJOR and I need to spill the beans. Promise not to tell anyone?"
Quickly follow that text up with, "Sorry, wrong person!" Your gossip-addicted friend will surely text you back, demanding to know your secret, but instead of filling them in, you can string them along all day before revealing that the major development is how gullible they are.
More April Fool Pranks
Fake head in bed
Use a mannequin head and place it next to your partner while they sleep. Wake them up and as they try to look at you they freak out as they see the fake head.
Insects in the lamp!
This one can really scare the crap out of someone! All you need is a pair of scissors and some paper. You'll need some skills as it isn't easy to cut out some insects!
Food pranks are among the best because they're easy to implement, and they generally get a big reaction, especially when someone gets something they don't expect.