Toys R Us have 25% off Hasbro Toys at the moment - though few of them are closer to 75% off! If you're spending over £30, remember to use the code BIRTHDAY9 to take £5 off too. Orders under £29.99 have a £4.95 delivery fee, but over that it's free.
That game that was almost 75% off is the Cuponk Game*, reduced from £9.99 to £2.99, which is pretty great.
If the classic board games aren't quite your thing, there's also Elefun and similar games!
Some of my favourite memories of family time as a child involved board games and puzzles - quality family time can be forged in playing away from screens. I recommend it!