Lagers are fermented with a bottom fermenting lager yeast (Saccaromyces pastorianus). These yeasts are able to ferment at lower temperatures than the top fermenting ale yeasts (Saccromyces Cervesiae). The result of this low temperature fermentation and maturation is a beer with a cleaner flavor profile (less esters, less higher alcohols) than its top fermented counterpart. The extended cold storage (lagering) also makes these beers more shelf stable than ales which explains why most of the world's beers are of the lager variety.
Because lagers ferment at lower temperatures than ales and yeast metabolism works slower at these temperatures, they take longer to ferment and also require more attention than ale fermentations, which makes them less attractive for most home brewers.
Bought a commercial Johnson Controls temperature management unit a while back from amazon, it cost about $70. It has a temperature probe that I stick into the 5.1 Cubic foot deep freeze I just bought (basically, about the smallest freezer you can get) for $180. I open the JC unit with a screwdriver and set the jumpers to kick off when the SP temp is met... in this case, 50 degrees. This means when the freezer cools down to 50 degrees inside, the power is cut off.
I set it to have a 1 degree range off SP before it kicks on and off, with a 1 minute minimum duration between when it can kick on after it kicks off (to keep it from turning on/off every second when at the threshold temp).
If we are at stable temps tomorrow.... brewing an Octoberfest lager. Exciting!
On a side note, The current Sam Adams seasonal is the Octoberfest... it is prolly my fave commercial beer available in Ohio (that I have discovered so far). Try it. It is why I am brewing my own.