This use-case is a pretty rare one, but in some circumstances, it can be very helpful. For example when you live in a student dormatory which only offers one 802.1x-encrypted LAN-port in your room, but you want to run your own wifi-network to be online with other clients, too, like your laptop or smartphone. In this case, normal routers with stock firmware won't help you out because most don't support this networking protocol. OpenWrt on the other hand offers you the possibility to connect your router (you could buy this one if you don't already have a suiting router) to the 802.1x-network via WAN and enable you to have an own, independent network. Here's how.
Important: before you attempt to do this, it is NECESSARY to ask your network admin if he/she is okay with your usage scenario. This can cause some trouble if you do it without permission, as many 802.1x-networks aim to prevent this exact use-case.
So here's the deal