I think Gaz was being funny…
again? 
As in “it’s happening again”
*said with a shocked voice*
it feels like it only just happened again.
Remember Gaz has been to this event the last 2 years

that time of year again 
Again I think he is joking about how it’s an annual event held at the same time each year and how it is a shock that it would continue at the same time again