Also I get asked alot from members of guild how to actually install addons .. w/o using a client .. I would like to share how I do it ..
I have been able to do this for most windows OS ..lets use solidice and OQ for example .

Hit download ..If you left the download defaulted { destination folder} to download folder ..simply open the download folder . you then should see the addon you just downloaded in that folder {oque with that version} now right click the addon as it is compressed .Now pick the option extract all..extract all inside the download folder .. it should now open a window containing the extracted unzipped folder of the addon . now just copy that folder that is unzipped .. proceeed to the tutor Ron has posted above to find the interface addon wow folder ...now in the list you can either delete the old Oque from that list of addons and then paste the new version in that list or let it override the older version if you did not delete it .now close all those folders and close the wow folders { while doing all this make sure the game is shut down } you can reboot but it isnt needed for most addons seeing they are not a exe file for your system .. open the game and check the addon list to see if the addon now shows .. goodluck

Im sorry I must be getting old .lol I did get the 1.8.8c now .. but I am embaressed to say , I had to move the OQ up more to see the full list , I am now seeing rbgs .. thanks for the reply and all seems fine now .. thanks again Ron

I forgot to mention its for world of warcraft .

Rbg with OQ missing

hello .. I been using this addon to finish any caps for some time now, by joining yolo rbgs . since the last few updates I installed... the rbg option seems to be gone ?I just get random bgs or battlegrounds in the list .. also all other things are showing up there . raids , cel bosses , arenas , randoms .. everything but rated bgs .. I am using 1.8.8 now with the same results .. any Info be awesome .Thanks