Software to Practice/ Exercise Openings?

I've installed Winboard, so I have a gp chess program to run thru games, now. Does anyone recommend (free <grin>😉 software or a website (like Chess Tempo, which is nice for some tactics and endgames) for working on openings?

There are so *many* named variations, it's hard to figure out which subset would be most useful to study.

I would maybe consider the option of looking at short games in a database like for example just go to chessgames for example or whatever database you prefer and type in show me games that are short like 18 moves or less.