Beet & Potato Salad (aka Russian Salad, Salad Olivier)

This comes together very quickly if you have cooked veggies on hand.
There are hundreds of variations of this salad, and the most popular "other" veggies to add are corn, celery, carrots, or onions. Some people even like adding tart apples - a nice variation.
The salad's at its best on Day 2, but that's hard to prove as it usually disappears during Round 1.
If you want extra protein, this goes ridiculously well with hard-boiled eggs and/or pickled herring. Chop and add, or serve on the side.

2 medium potatoes, cooked, peeled, and diced
2 medium beets, cooked, peeled, and diced
1 cup green peas, cooked
(optional veggies: see above list)
2 medium dill pickles, diced
1 cup sour cream or mayonnaise
1 tablespoon fresh lemon juice
salt and pepper to taste
dash of sugar (optional)

In a large bowl, mix the sour cream or mayonnaise, lemon juice, salt, pepper, and sugar (if using). Blend well, then add in the potatoes, beets, peas, pickles, (and any optional veggies/ proteins). Chill for an hour or two before eating.
Very nice served in crisp lettuce leaves.