?

Hey, so i was playing an online game and all of a sudden I started to get these lag spikes every second. So it made it virtually impossible to play. I have a Motorola Router hooked up and a bunch of us are using it, which can cause the internet to slow down, but why would it be fine and then spike and then be fine again ect..?

I connected to my router and looked at who was connected to it and their speed. I kept refreshing the page really quickly and my speed kept going from 65000 (kbps) to 6500 (kbps) and back so i figured that this confirmed what was happening.

So my question is; what causes this, and how can it be fixed (if it can). Thanks