The other day I managed to salvage about 4-5 kilos of magnsium sulphate that was going to be thrown out. Anyway i'm at a complete loss as to what to do with them and I need some ideas. My only idea was to use them as a drying agents but i'm sure there is something more interesting I can do. Any ideas?

feed it to Tomato plants, they love Magnessium

Magnesium sulfate in fact is not such an interesting chemical. You can do some precipitation experiments, but that's all. You indeed can use it as a fairly powerful drying agent, when it is calcined and the crystal-water is removed from the chemical. As YT suggested, it also is used as fertilizer.

In certain pyrotechnic compositions it also is used as a high-temperature oxidizer, but that is very hard to ignite. I have understood that it can be used sometimes for white flares, but I must admit I'm not a fireworks expert, so someone else may jump in to give more info on that.

You could make copper sulfate by electrolysis and cu electrodes

It can be used to grow nice crystals easily. As drying agent it is sometimes better than CaCl2. It can be used for electrolysis experiments, as source of sulfate ions or for etching (or dissolving) some metallic anodes. It can also be used to make other magnesium salts by first precipitating it with alkali metal hydroxide or carbonate and then reacting with suitable acid.