To be honest, I wouldn't get carried away with phonics at 3 (they'll have to do it at school anyway, and it gets boring for them). That said:
Reading, lots! Rhyming books are great, but just a variety of books.
'Sound bags', find lots of things beginning with the same letter (e.g. banana, ball, bag, boomerang etc), talk about them and practise the letter.
Alphablocks on CBeebies is good.
Recognising letters, ones in their name are a good start.
As for numeracy, lots of counting!
Counting carrots as they go in the trolley at the supermarket, Lego blocks as they get tidied up, socks in the washing basket etc.
Baking is good; counting scoops of flour, weighing out ingredients (more of less).
Building things with Lego; "...build a tower with 7 red blocks" for example.
Numberblocks on CBeebies is good too!
Counting books, songs and rhymes.