If they have WiFi then you can use Amazon Fire TV Stick or Google Chromecast or Roku Streaming Stick
I've only tried the Chromecast but it worked nicely. The Chromecast plugs into a HDMI port which you probably won't find on an old TV but you can you can get an HDMI to Component adapter and it will be pretty good. HDMI to Composite will also work but video is not as good. Amazon and Newegg have them. You will also need cables 3 component + 2 audio or 1 Composite + 2 audio as most adapters don't come with cables. There is a small power adapter that will need a place to plug into.
Option 2: (not as nice since to play a video they will have to get up and walk to the TV to run it (Unless you add a wireless mouse and keyboard) and it ties up the laptop. )
It appears the G6 has an HDMI output so you might try directly connecting it to the TV (or with an adapter) but there have been a lot of complaints about the G6 see: