I am a big fan of using foam rollers for myofascial release, especially after workout.
There are a lot of foam roller products for myofascial trigger point treatment out there, but I am too cheap to buy a piece of recycled plastic pressed into a cylindrical form for 20 EUR or higher. This is one of the easiest DIY projects possible, so make your own!
The standard foam rollers of different sizes can be replaced with almost anything that has a similar form and supports your weight. I used PVC tubes from a hardware store nearby. Just chose your preferred diameter, cut of the flange (using a Dremel or a standard saw) and you are done.
The small version can easily be replicated by putting two tennis balls into nylon tights and tying a knot at the end. This might sound/look a little strange, but seriously it works well (although the tennis balls are almost a little too soft).
Happy foam rolling!