Looking for an inexpensive way to plot temperature

New brewer here. I have my first 2 batches in fermenters right now. I am quickly learning that it's all about temperature control.

I found a decent $11 digital thermometer with 2 temperature sensors and a min/max setting. I used a few to check spots around the house, as well as to monitor ambient and fermenter temperatures for the batches in progress.

But these thermometers have disadvantages. For one, if you handle them (say to check min/max) the heat from your hands will register on the internal sensor. (The probe, attached to the fermenter, is OK.)

A simple min/max is only part of the story anyway. So, I am looking for a way to capture temperature data over time and plot it... without a nearby computer turned on to capture the data all the time.

If anyone has found a gadget they like, I'd appreciate a pointer.

You are looking for a temperature data logger. The make them that are battery powered and plug into your USB port to download the data. Prices start at around $50 for the simple ones that record abient temps with an internal probe. Here is one that has a thermcouple probe, for $90.
http://www.microdaq.com/lascar/temperature/thermocouple-display-logger.php

I have not used any these but they should work.
You might consider getting one that has IP65 rating, meaning it is water proof.

I was going to get a HerpKeeper to control my fermentation chamber and it has the ability to graph temperatures. I used the ReekKeeper on my reef tank and I was happy with it. Not really that cheap though 120.

http://www.digitalaquatics.com/herpetology/systems

Great leads, thanks guys!