Learn English – slang word for “electronic cigarettes” (e-cigarettes)

Cupid might be a good idea.

Play Cupid: to try to arrange for two people to fall in love.

He was playing cupid when he introduced John to Sheila.

According to ldoce:

a character based on the Roman god of sexual love, who was the son of Venus. Cupid is usually shown in pictures as a young boy with wings, holding a bow and arrow . His picture is often used on Valentine card s to represent love. People sometimes say that they have been hit by Cupid's arrow when they have started to have romantic feelings for someone.

Accroding to MSN Dictionary:

Synonyms for matchmaker: marriage broker, go-between, fixer, intermediary, cupid

Piece of junk refers to something that is cheap, shoddy, or worthless. It can be used as an oject as in "This piece of junk won't boot." or a modiying adjective as in "This piece-of-junk computer won't boot" (with or without hyphens).

Related adjectives can be used with the name of the device. These include:

"Junky", "shoddy", "trashy", "lousy", "worthless", "crappy" (oh, and, of course, "shitty").

Boat Anchor which merely means the device is only suitable for that purpose. "This computer has become a boat anchor" (Urban Dictionary, definitions 2 and 3, Ham.net shows the term used in practice.)

Doorstop similar to "boat anchor". "This computer only works as a door stop now."

Junk Box No longer suitable for anything except to be cannibalized for spare parts. (See wikipedia.) Usually this refers to just the parts themselves, already disassembled and collected into a box. But it parallels your German reference, so I thought it was worth adding.

We also refer to some things as "hangar queens", which is alludes to aircraft that spend more time in repair than they do in service. Any products that can't get through the production process may be relegated to being hangar queens, with hopes that someone will eventually figure out how to repair them.