The website www.vfxtalk.com has a competition and challenge going on:
Download a provided daytime image (470k Jpeg,) and modify the shot to be a night time shot... You can adjust and add any fun night-time goodies or effects you wish, such as moons, stars etc. You are reqested to also remove (paint out) the foreground cars and people.
You should use any of the 2d software from the listed forums at VFXTalk.com - see the list at: http://www.vfxtalk.com/forum/
Note: anything further that you want to add to the shot to enhance or besutify it, such as adding the flying car from Harry Potter, or the USS Voyager ...whatever.... is completely up to you.
The main emphasis is on creating a night time shot from the plate. Submit your entry before the LAST DAY OF MARCH. You are encouraged to ask questions and seek help at the VFXTALK.COM software forum of your choice.
See the complete VFXTalk.com rules here:
Members will VOTE for the best shot. The winner is requested to post their workspace as a tutorial.
Check it out!