Possibly the first WiFi throwie. Held in place by a magnet, this captive portal features its own local web- and dns server. Hence the name: CaptiveIntraweb. In its current form it serves Java script games to its visitors. But the possibilities are endless...
Based on the inexpensive ESP-01 module (ESP8266), it runs a slightly modifies NodeMCU firmware. The material costs about 10€. Updates will be published on my blog at: http://www.AReResearch.net