Here are some genera that have mostly very easy to grow species. Argyroderma if watered carefully because they split easily. Bergeranthus, some Cheiridopsis eg purpurea, Corpuscularia lehmannii & taylori(are almost indestructable but often sold under the old classification of Delosperma) The true Delosperma that are mostly best planted out. One of the best 'window' plants is Fenestraria if watered carefully thru the cooler months, also robust Gibbaeum spp such as petrense,& velutinum, all Glottiphyllum, Hereroa, and Ihlenfeldtia, Lampranthus are spectacularly garden plants, as are Malephora, others are Mestoklema, Neohenricia, Oscularia, Pleiospilos with some nice 'mimics', Rhinephyllum, Rhombophyllum, Ruschia, Schwantesia, Stomatium, Titanopsis calcarea, Trichodiadema,
Many of these plants will rest (become dormant) or have a strong tendency to rest in summer especially in very hot conditions. A plant at rest cannot utilise much water so too much may cause rot. For a beginner it is probably best to expect best growth in autumn or again in spring if the plant needs to catch up as it were. Water virtually all year but according to your plants needs. Never keep soil constanly damp. If they seem to be resting ease off. If they are in full growth and especially if in flower keep watering. With experience you will learn just how and when to water by observing your plants in your own unique environment and cultural regimes. There are no hard and fast rules. A good general rule for winter growing mesems especially is water little but regularly. Many love frequent (even daily) evening misting however this is of little value for Lithops that are very different in needs to most other mesembs. Lithops have incredibly impervious skins. The generally winter growing Conophytum love mistings. Yahoo groups Mesembs will give you a lot of information.

This is an excellent site for expert help

Here is a link that might be useful: The mesembs

The harder question is where can you obtain Mesembs! I have 2 Lithops species as well as Bergeranthus scapiger which I have seeds of if anyone is interested in a trade.

Hobbes

It is highly probable that there will be a large selection of rare mesembs for sale at the next CSSQ Show, Queen's Birthday Weekend at the Mt Coot-Tha Botanical Gardens Brisbane. Cheers

Here is a link that might be useful: The Mesembs