The aediles were originally two subordinate officials from the plebs (the general body of Roman citizens). They assisted the tribunes in maintaining the prisons and supervising the common temple. Later their duties were extended to include the administration of public buildings in general. In 367 B.C. an additional two aediles began to be elected from the patrician class.
The position was an elective office with a one-year term. Their duties were threefold: cura urbis (looking after the streets and the water supply, maintaining public order in religious and cult functions, and supervising weights and measures), cura annonae (maintaining and distributing the grain supply), and cura ludorum sollemnium (administering the public games). Julius Caesar created special aediles ceriales to look after the grain supply.
As you can imagine, the aediles administered matters close to everyone's heart, like food and water! But their greatest advantage was the supervision of the public games. Especially for rich men with political ambitions, this was a plum position that could lead to greater things. The aediles bore most of the expenses of the games as a means of gaining popularity and votes.