The campaign, running on Nestle Purina's new 12 x 400g Felix offering, sees 2-for-1 activity vouchers inserted into packs.
There are two booklets of vouchers to collect. The first offers 85 activity-based "big days out", including paintballing, go-karting and ten-pin bowling.
The second has 100 options, including visits to theme parks, museums and wildlife parks. Vouchers are redeemable until February 2006.
"This is a highly targeted campaign that really focuses on offering added value to families," said Noel Clarke, Felix brand manager. He added that the new multi-pack would be a key product offer for Felix in future.
The activity, through Geronimo, is aimed at driving sales of the multi-pack and rewarding customer retention.
"The big days out booklets will encourage people to trade-up to the multi-packs," said Geronimo group account director Sara Harris.
"Consumers will then be encouraged to continue buying Felix through the offer of more vouchers to collect and more days out to enjoy."