Roadbuilders is a small variant on Carcassonne playable with the basic set or any of the expansions. It makes completing roads worth points even if you do not have a meeple on the road. Use this for some added flexibility when you're out of meeples and need to sneak in just a few extra points.
Whenever you place a tile that completes a road, look for any tiles on that road that also have city segments on them. For each pennant on those cities, score 2 points. You can score these points even if those cities are not yet complete.
In the example above, the road highlighted in blue is adjacent to two cities bearing pennants. All totaled, there are four pennants on those cities, so the player who completes that road would score 8 points.
Also in the example above, the road highlighted in orange is adjacent to two cities with a total of three pennants, whoever completes that road scores 6 points.