Ping jumps all over th place

If anyone else is using the internet at the same time, that could be the cause. Especially if they are watching youtube videos because when you watch youtube videos its actually downloading the video file, which you probably already knew. Also make sure theres no programs such as utorrent, bittorrent ect... If they are seeding or uploading or downloading then that will also cause issues.

yep any1 using the web will cause your ping to jump. reason being every time they connect, click a button or load a video information is being queued ready for transfer. as the connections build up your ping will increase. and as each connection can take up to 30-65 hops on its way to a server any of which can have an issue, resulting in your ping increasing...

open your router and put your pc at the top. put everything else under it and if you can limit there priority (some routers allow this as the have a gaming mode). if your router has multiple Ethernet ports use em. rather than using wireless. particularly if the other user is in the same room... if not you can get an ethernet block which plugs into the house electrics. you plug it in upstairs and plug another downstairs by the pc. the kid use this and dont need to use the wireless at all. as it basically makes your house electrics into a big Ethernet cable.
look it up b4 you spend money on it though... as it may not work for every 1.

hook up with a cable and see if the problem goes away