Passing parameter to controller from route in laravel

You don't need anything special for adding paramaters. Just like you had it.

Route::get('groups/(:any)', array('as' => 'group', 'uses' => 'groups@show'));


class Groups_Controller extends Base_Controller {

    public $restful = true;    

    public function get_show($groupID) {
        return 'I am group id ' . $groupID;
    }  


}

This is what you need in 1 line of code.

Route::get('/groups/{groupId}', 'GroupsController@getShow');

Suggestion: Use CamelCase as opposed to underscores, try & follow PSR-* guidelines.

Hope it helps.