Use a Wireless Ethernet Bridge
Whether you are an administrator or just plain user of the Enterprise network, you may be able to use a wireless bridge to connect your non–802.1X devices. The computer or device must have an Ethernet port, and the wireless bridge must support WPA/WPA2-Enterprise (not just WPA/WPA2-Personal or PSK). If this is the case, you could configure the bridge with the authentication and encryption settings so it connects to the Enterprise network and then plug it into the non–802.1X device to give it network access.
If you don't want to purchase a wireless bride, you may be able to turn a wireless router into a bridge by using the aftermarket DD-WRT firmware. But keep in mind, WPA/WPA2-Enterprise is supported only in the Client Mode of DD-WRT if the router is loaded with an Atheros Wi-Fi chipset. You can check the compatibility of routers with DD-WRT and the chipset used via DD-WRT's Router Database.
If the router is supported and is using an Atheros chipset, you could flash the router with the firmware using their instructions. Then you could configure the DD-WRT router in Client Mode to connect to the Enterprise network.
Finally, you could connect non–802.1X computers and devices to the Ethernet ports of the DD-WRT router. Since NAT is used, they would be on a separate subnet of the Enterprise network. Thus the Enterprise network only thinks the DD-WRT router is connected as a client and doesn't know there are multiple clients connected through it.