I need 8am to 6pm cover to allow for work and commuting, and sometimes I need longer than this. DH's current job means he is away a lot and so can't help out except when he is actually on holiday himself. He is trying to get a local job but it is not proving easy in the current climate. It is a nightmare, my DH and I rarely have a day off together and what is a family holiday, I think we had 3 days together 3 years ago? We use a combination of:
Use the nursery they were at til they started school which has a holiday club - very small and fills up quickly, book early or problems - also my eldest doesn't like this any more as it is geared to infants really and he is now 8. My 4 year old loves it.
Use our childminder when we can - she is often not available at holiday times - on holiday herself or simply full up with little ones. She is great and there is an older boy there for DS to play with.
There are various activity clubs but they tend to be 9/10am - 3pm which is of no use at all without additional help.
Occasional swap with 1 or 2 other mums - this does mean I tend to host their kids all weekends term time and to be honest it gets too much - so I use this for last minute emergencies only. Also useful though re sports clubs if both kids go to the same one.
We do have grandparents an hour away but they are getting too frail to look after an 8 year old boy plus 4 year old sister on a regular basis all day long. Having said that what they do brilliantly is come to stay at our house and take the kids to the childminders for the day and then pick them up. They can manage this and it means I can work normal days. They can also ferry kids to sports clubs and then back to the childminders - which is great for my cricket mad 8 year old who would otherwise miss out.
Try to work from home - which in reality means attempting to work all day and getting a few bits done and then working all evening and night to actually complete my cases.
At the end of the Christmas and summer holidays I am a wreck. It takes a couple of weeks to recover!