In natural language dialogue, the way a responder 'takes up' the initiative of a participant, largely influences the further course of the dialogue. This uptake mechanism can be understood as a negotiation at a meta level: an initiative counts as a bid of a dialogue game; an appropriate response counts as an acceptance of the bid. We propose to extend this account of uptake to other conventional joint activities besides dialogue. We show that for an uptake mechanism to be effective, a joint activity must be characterisable in terms of initiatives and responses, with projection rules that indicate what initiatives count as a bid for a joint action, and appropriateness rules that indicate what responses count as appropriate. © 2006 Elsevier B.V. All rights reserved.