The single-board computer space is getting crowded, and Orange Pi is yet another fruit-flavored Raspberry Pi clone, from China based Shenzhen Xunlong Software. The Orange Pi Zero is their smallest model, but still packs a H2 Quad-core Cortex-A7 ARM CPU; Mali 400MP2 GPU; 512 MB RAM; 100Mb/s ethernet RJ45; and 802.11 b/g/n wifi. The basic board also gives you one USB 2.0 port, while the add-on board gives two more, plus audio, IR. It also has additional GPIO pins, similar to the RPi. Both boards, and a case can be had for $20 from DealExtreme. An even smaller case, containing only the main board is also available.
Compared to the RPi, this board is almost half the size, and half the price, but still includes wifi. The only downside is that there is no HDMI, and TV composite video out is complicated. Even with a wide offering, Shenzhen Xunlong Software is far behind the Raspberry Pi Foundation when it comes to mind-share and community support. That shows in details like the OS distribution download page, where none of the links from product page where satisfactory: Most where old, and others didn't work at all.
Instead, the Armbian based distributions worked well. Both the Ubuntu and Debian images booted without problems. They both connect to the wired network port with SSH enabled. At first login as root, the password is 1234, but you are immediately prompted to change it.
Given it's very small footprint, and power (micro USB) as the only required cable, it could easily be hidden or even hide in plain-sight among the usual cable clutter under any office desk. It'd make an excellent spy device, and could be used to listen in on conversations or network traffic. Or conversely, watch out for inconspicuous small boxes around the house or office.