Using OpenKeyVal (http://openkeyval.org/), the bookmarklet looks like this:

    (function(){
        var data = { data: location.href }
        jQuery.post('http://api.openkeyval.org/myownkey', data)
    }())

And on each client you have a screen-sized iframe + an "update" button that triggers:

    $.getJSON('http://api.openkeyval.org/myownkey', function(data){
        iframe.src = data
    })

You have to remember to use your local IP address, not localhost. I ended up making a small nodejs server so we could use websockets and drop the update button.

You can do something similar with Synergy. Laptop acts like another monitor, e.g. mouse over to the left and your keyboard and mouse now control the laptop, and cut&paste between machines mostly works too.

Synergy works well, although it is old and unobvious how to set it up. I haven't seen anything better yet :-) However, I only used it between Linux and XP (I use virtual machines now).