Simutrans is a freeware and open-source transportation simulation game
Your goal is to establish a successful transport company. Transport passengers, mail and goods by rail, road, ship and air. Interconnect cities, districts, public buildings, industries and tourist attractions by buiding a transport network you always dreamed of.
Control and watch your finances and the traffic of your vehicles and goods. Start in 1880 and finish in 2050. There will be new vehicles and buildings throughout this time.
Considering its a freeware game and graphically its nothing special, it is worth a go when you really are that bored and have a couple hours free to waste!