2head spare turns?

[Noblellama]

If I'm playing 2headed giant and I cast {Part the Waterveil} do both my teammate and I get another turn?

[Indianslayer]

Yes because part the waterveil give you an extra turn, the team as a whole takes an extra turn.

805.8.: If an effect gives a player an extra turn or adds a phase or step to that player's turn, that player's team takes the extra turn, phase, or step. If an effect causes a player to skip a step, phase, or turn, that player's team does so. If a single effect causes more than one player on the same team to add or skip the same step, phase, or turn, that team adds or skips only that step, phase, or turn. If an effect causes a player to control another player, the controller of that effect controls the affected player's team.

Rule for reference.