So reddit is a social community where people post articles and links of interest and comment and discuss topics of interest. Subreddits focus on a particular topic.
- http://www.reddit.com/r/iama — I Am A (Ask Me Anything), where people with interesting jobs or life experiencesanswer whatever questions reddit has for them (after providing proof of their identity, often by tweeting a link to the reddit post). President Obama has done this, as have the Mythbusters.
- http://www.reddit.com/r/Assistance — Assistance. People can ask for (or offer) advice or material assistance. Whether they get it is up to the crowd, not the moderators. Top posts right now range from a request for money to finish nursing school to one for $20 for gas and groceries to an offer of some food to any needy Las Vegas-area resident.
- http://www.reddit.com/r/RandomActsOfPizza — Random Acts of Pizza. Like Assistance, but with much more limited scope. Redditors can request or offer gifts of pizza to those who are in need or simply want a pizza. Notably, Random Acts of Pizza flooded every Boston-area police location with pizza after the Boston bombings in thanks for their efforts. Reddit loves pizza.
- http://www.reddit.com/r/secretsanta/ Secret Santa/redditgifts, combination gift exchange and online marketplace. The basic purpose is to facilitate Secret Santa-style gift exchanges among redditors each year.