Jammers

n.

Heard in Dublin, Meath, Sligo, Limerick and Waterford

A venue or pub that is extremely crowded.

In use

Went to dat new o2 tingy t c britney nd it was jammers wit d fans

Posh English

I attended that novel arena to witness Miss Spears perform, and it was entirely packed to the rafters with admirers.

Same phrase, other counties