I've had some good ones over the years, although my mother has been my favored target. I think the key to a good April Fool's joke is to hit someone with enough realism and enough stock in something plausible to make it believable. Of course having a gullible target who is always wound up helps too. Past April Fool's Pranks on my mother include:
telling her that I dropped the cake as I was taking it out of the oven and that glass and cake were everywhere (age 12)
calling up to tell her that I was in jail and need to be bailed out (age 19)
calling to tell her I'm pregnant (age 20)
telling her that I had a bad car wreck and that the car was totaled (age 18)
calling to tell her I was in the hospital (age 20-something)
not pulling a prank on her all day, when she finally was expected it (last year, ahahah, that was a good one! I've never seen her madder)
There's been soooooooo many....I just love to freak my mom out. And seriously, if I've pulled a prank on you every year for 15 or so years, aren't you going to start paying attention to what day it is? Which is why last year, when my only prank was not pranking her, was so priceless. I bet she was a nervous paranoid wreck all day *giggle snort* Only problem is, I don't have anything to prank her with this year.....and it seems mean....but a nice easy going prank would be nice....hmmmm...