Kvetka is an interesting tool for watching and analysing (though not playing) chess games.
You can use it to open PGN, FEN and other formats, as well as viewing online chess games from many popular web sites, or pasting games from the clipboard.
The program comes bundled with the Stockfish engine for analysing games, although it works with other UCI engines too.
Launch Kvetka and it displays an opening board, along with your list of games, which initially just has a single "Anonymous vs Anonymous" placeholder.
To get started, we went to chessgames.com, selected one of the "Hot Games" and copied the URL to the clipboard (http://www.chessgames.com/perl/chessgame?gid=1044727).
We then double-clicked Kvetka's placeholder game, right-clicked in the empty "Moves" box and selected Paste > Load.
The details of the game (Spassky vs Fischer) appeared in the list, and we were able to follow it move by move, or by jumping directly to any move of interest.
Kvetka also allows you to flip the board, move and place pieces, copy position data or game screenshots to the clipboard, run and view your analysis, and more.