As packed as sardines in a can.

As cold as ice.

As busy as a bee.

These are just a few examples of well known similes, or figures of speech, that are used so often, they can become cliche.  Why not use your imagination and power of observation to create new, more interesting ones?

As packed as an 8am marshrutka.

As cold as frozen salo.

As busy as a babushka.

You can find more information and a list of well known similes here: http://www.englishclub.com/vocabulary/figures-similes-list.htm

Give your students the list and ask them to create new ones.  Then ask them to use their new similes in a sentence.

The classroom was as packed as an 8am marshrutka.

Her hands were as cold as salo.

The students were as busy as babushkas the afternoon of the concert.

Happy writing!