I joined a homebrew club that has a club wide competition at each meeting (once a month). We normally have 20 to 25 beers, most are focused on the style selected as the theme for the night, a pitcher is filled for each beer and passed around for everyone to take samples of. Each member fills out a bjcp score sheet, the numbers are tallied, the outliers are dropped, and standard deviation factored in. All in all scores I think are much higher than normal competitions (averaging in the 30s), but you still get an idea of how your beer fares, and you get tasting notes from about 30 people.
It's a nice layoff back intro into competitive brewing and judging. So if you want something like that, look around for a club in your area.