Government bonds run for varying times, with various rates of interest. You can take some out for a few days if you wish....my bank did that for me last week when I wanted to merge 2 accounts together and there was a delay between dates on the 2 accounts.
They are easy to take out, from any bank. You can invest any amount you wish in multiples of the bond value. The tax rate is 10%.
At the moment I would also look at time deposit accounts with the banks...usually for 30-45 days. Although you do pay 15% tax.