Competitions:
Listing of local competitions with approximate schedules. If you are interested in judging or being a steward, contact the competition organizers; there is always room for extra stewards and judges.

Temperatures and Why

Temperature Activity Duration Effects
95'F/35'C Phytase (Acid Rest) up to 2 hrs. Lowers pH,
makes more acidic
122'F/50'C Proteolysis (Protein Rest) 15 min.- 1 hr. Proteins broken into amino acids
140'F/60'C Beta-amylase starch conversion into sugar. 20 min. - 1 1/2 hr. Produces a highly fermentable wort (thinner beer)
150'F/65'C Alpha & Beta-amylase equally active 20 min. - 1 1/4 hr. Produces wort with both fermentables and nonfermentables.
158'F/70'C Alpha-amylase starch conversion into dextrins (unfermentables) 20 min.- 1 hr. Produces a wort high in unfermentables (more body)
168'F/76'C Amylase activity stopped 5 - 15 min. Aids in liquefying wort for better run off.
170'F/77'C Sparge Water temperature 30 - 60 min. "Washes" sugar from grain bed, but too high temp could extract tannins

source: http://www.brewsupplies.com/mashing_temperatures.htm