How to access model hasMany Relation with where condition?

I think that this is the correct way:

class Game extends Eloquent {
    // many more stuff here

    // relation without any constraints ...works fine 
    public function videos() {
        return $this->hasMany('Video');
    }

    // results in a "problem", se examples below
    public function available_videos() {
        return $this->videos()->where('available','=', 1);
    }
}

And then you'll have to

$game = Game::find(1);
var_dump( $game->available_videos()->get() );

I think this is what you're looking for (Laravel 4, see http://laravel.com/docs/eloquent#querying-relations)

$games = Game::whereHas('video', function($q)
{
    $q->where('available','=', 1);

})->get();