My friend Asare introduced me to these so I bought a few. They are pure essential oils in an organic base. You basically rub them on your pulse points when you need to.
They are really good, produced by Neals Yard. They come in 4 varieties – Energy, Night Time, Relaxation, Travel and Study. You can but a pack of 4 for a discount. Generally, I think their products are a bit expensive but these I found to be quite reasonable.