An article in the March/April copy of "traders" mag referred to the 3.20pm-ish time as a common reversal time, along with 2.50-3.10pm and seven other common times : the main factor for the earlier one, and the big market volatility at open is the execution of orders that have been given overnight, and are placed first thing in the morning, hence thats why a lot of people advocate staying out of the market for the first 20mins.
The complete list of times the article said to note were (all in EST)
9.50-10.10
10.25-10.35 (your one)
11.15-11.30
12.00-12.15
1.15-1.30
2.15-2.30
3.00
3.30
Some of these you could probably put down to lunchtime trade. The others I dont know about, but there are some fairly good results to be found backtesting these theories. I dont know if these times are something that Sunseeker uses on his daily US chart...