Apparently there are teachers and police officers with such a complete lack of science literacy that consider any digital clock to be almost a time bomb, especially if a boy with a muslim name is involved.

As a new high schooler, Ahmed Mohamed thought he’d show off his Maker prowess by bringing in a simple digital clock he built at home in about 20 minutes, he told the Morning News. Instead, a teacher decided a circuit board plus wires must equal one thing: mortal danger.
[…] By mid-afternoon, police were leading the boy out of school in handcuffs and taking him to juvenile detention on suspicion of making a “hoax bomb.”

More details as well as instructions on how to make your digital clock on Wired
(Photo originally posted on Twitter by Anil Dash. Yes, the boy is wearing a NASA t-shirt)