Here a nice graphic temperature recorder.

Features
It shows 60 samples. (new values scrolls left the plot)
Temperature is sampled every 15 Sec. and averaged.

The following parameters are configurable.
Sampling rate 15 Sec. to 3.825 Sec.(255*15)
Initial scale -30°C to 90°C
Scale resolution 1°C to 20°C division
Display contrast level

Configuration parameters are stored in eeprom.
To change parameter only the eeprom must be reprogrammed (NOT the code)
Refer to source code to know where they are stored.
N.B. Negative temperature for the initial scale value must be stored in 2 compliment form.

Source code attached.
(sorry for the Italian comment in the code, i have not time to translate)
Regards
Gianni