I use olive oil, coconut oil and honey. To stimulate the scalp, I add 2-3 drops of peppermint oil as well. Many times I'll mix this with a condish for a prepoo.
For an easy but really effective hot oil treatment I just warm a few tablespoons of Hot Six oil and apply it directly to my scalp and hair with a color applicator. I just started using this product and I really love it. I follow with a shampoo (Paul Mitchell Tea Tree Oil) and whatever conditioner I have nearby (usually Organix or HH Hello Hydration). HTH
Its not quite a hotoil treatment, but I sometimes put olive in some conditioner and put it on my hair with a cap on and wash it out in the morning. My hair loves it.