How you can make and receive Google Voice phone calls from any old wired phone:
http://www.zdnet.com/article/google-voice-a-cheapskates-guide-to-cheap-voip/

This project: The Ultimate Google Voice How-to Guide (2014 Edition)

The OBi, from a company called Obihai, is a tiny box a little smaller than a 4-port Ethernet switch. It came in two variants when I used it back in 2011, the OBi100 (for $39.99) and the OBi110 (for $49.99). They've since added the Obi200 and the Obi202 (moving up to $59.99 and $69.99, respectively). The company was nice enough to send me an Obi202 to look at, but I used the Obi110 for my phone solution for about a year.

Google : using the Obi with Google Voice

Google Voice now officially supported on OBi VoIP devices

http://the-gadgeteer.com/2014/09/12/google-voice-now-officially-supported-on-obi-voip-devices/
SEPTEMBER 12, 2014

Today on the Obhai blog, they have announced that there is finally official support for Google Voice! This is great news for users who want the convenience to use their Google voice number with a regular phone line. They are currently running a promotion where you can get the OBi200 at Newegg for $29.99.

More on Obihai product on newegg.

(1) Obihai OBi202 VoIP Phone Adapter with Router – Google Voice, SIP & T.38 Fax Support

1x USB for Obihai Accessories OBiWiFi and OBiBT

(2) Obihai OBIWIFI Wireless Adapter for OBi202

Type: Accessories
System Requirements: OBi202 VoIP Adapter with USB Port High-Speed Broadband Internet Wi-Fi Access with Support for the 802.11 b/g/n Wireless Standard Computer & Ethernet Cable for Configuration
Features: Use with the OBi202 VoIP Phone Adapter to Connect to Your Router via Wi-Fi Wireless Data Encryption with 64/128-bit WPA, WPA2 Wi-Fi Standard 802.11n - Also Compatible with 802.11b/g OBiWiFi Connects to the USB Port of the OBi202 and is Configured via Your Web Browser Supports Wi-Fi Protected Set-Up (WPS) when Paired with a Router Supporting the Same.
Model #: OBIWIFI
Item #: N82E16833617004

Google Voice for the home - Obihai SIP/VOIP devices and porting landline number to Obihai/Google Voice.

January 04, 2015

Obihai Technology is marketing Google Voice use with their Obi VOIP-landline bridge products (SIP & OBiTALK VoIP services, $40 on Amazon).

Unfortunately there’s no way to port a landline number directly to an Obi device. Instead you have to use the T-mobile hack - port to T-Mobile then port to Google Voice (best documentation of this hack I’ve seen by the way). Once you’ve made this irksome port however, you do get to use GV’s great features from a home landline and VOIP. (Compare, however, to mix of GV, Bluetooth, Mobile, landline.)

Alas, the future of Google Voice is problematic — we know it’s going to be replaced by Hangout, but we don’t know what Google Voice features will survive.

Still, it’s amazing to watch the twisty-turny evolution of voice communication. This is NOT what we expected back in 1994; then we expected voice communication to become essentially “free” by 1998. Remember that the next time someone predicts the evolution of the marketplace based on technological innovation. The market is very good at fighting back - for example. (Use a fax machine lately?)