Бить баклуши (Bit' baklushi)

Literally: To beat the baklushi

Example: “Все убирают двор, а он бьёт баклуши.” — Everyone is clearing the yard while he twiddles his thumbs.

English equivalent: To twiddle one's thumbs

Origin: Баклуши were rough wooden blocks split from aspen logs, from which spoons, ladles and other small wares were carved. Vladimir Dahl, and many after him, explained that splitting the blocks was the easiest work in the trade, so "beating baklushi" came to mean doing next to nothing. The phraseologist Valery Mokienko doubts it, since useful work, however easy, is no picture of idleness, and suggests the баклуша was the wooden piece knocked over in the game of городки. Russian Wiktionary gives both explanations.