I've just listed some fun striped paper straws in my Etsy shop. They are sold in packs of 25 of the same colour and come with a DIY printable file consisting of pennants/flags in a colour of your choice - an excellent way to add a personal touch in your colour scheme.
The straws themselves are made from paper, but nice and sturdy so you don't have to worry about them becoming soggy. I'm still deciding which of the three colours are my favourite. I love the cheerfulness that comes with the red and blue, but the versatility of the grey will probably make them my favour. They will look so great with pink or yellow flags or even silver shimmer pennants for a more formal affair!
You may order the red straws here.
The grey straws can be found here...
... and the blue straws here.
You are very welcome to e-mail me at almostamsterdam{at!}gmail.com, should you have any questions!