Yes...go to Challenge History, select SHOW ALL filter, then select the entire page and dump into Excel or other spreadsheet and work the numbers. Others have done it in the past and posted the results but no one recently that I can recall.
ALL CHALLENGES Total Entries = 201,497
Average of high Scores = 7.328
Overall average score = 5.3867
Average of median Scores = 5.3657
Average of low Scores = 3.3242
Total Votes = 44,188,161
Avg # Votes = 215
Total Comments = 2342
Avg # Comments = 12
2008 Challenges Total Entries = 30,941
Average of high Scores = 7.2583
Overall average score = 5.4423
Average of median Scorese = 5.4278
Average of low Scores = 3.4420
Total Votes = 5,750,429
Avg # Votes = 193
Total Comments = 1587
Avg # Comments = 10
I know I am going to sound like a complete nerd in saying this, but throwing these into excel will give you a decent idea, but it isnt completely accurate. Because some challenges have more votes, they weigh higher toward your own personal average than a challenge that has few votes.
Again... I apologize for my geekdom. I will go away now. :D