These are the worlds strongest permanent magnets - and they're relatively cheap and easy to find. They're great fridge magnets, a small one is easily able to securely nail the big calendar you'll get in your Christmas stocking to your fridge. I recently bought 100 x 3mm x 5mm Neodymium magnets from ebay for $17 - they're so much fun and they dont need batteries !
1 word of warning - the larger ones can give you a nasty pinch & blood blister when they snap together so be careful ! (they're also quite brittle).
This ebay store sells all kinds of neodymium magnets in Australia;
http://stores.ebay.com.au/Frenergy-Magnets
