The Obs Challenge did have a revival. I & a few others compiled several Obs Challenges in the Obs. & Visual forum. The link below will take you to a thread in the Beginners Forum where a list of them is noted:
http://www.iceinspace.com.au/forum/s...tion+challenge
If there is more interest in providing fresh challenges, I can look at setting new ones.
I hope this helps.
Mental.